tools/devshell/contrib/bazel2gn

#!/bin/bash
# Copyright 2024 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Source tree
#### PREBUILTS=${PREBUILT_BAZEL} ${PREBUILT_BUILDIFIER} ${PREBUILT_GN} ${PREBUILT_JQ} ${PREBUILT_PYTHON3}
### Syncs BUILD.gn and BUILD.bazel for targets that are dual-building in both.

## usage: fx bazel2gn [-d|--directory <path/to/dir>]... [-h|--help] [--no-build]
##
##   -h|--help       Print out this message.
##   -d|--directory  Directory to sync, repeatable.
##   --no-build      Skip building required dependencies.
##
## Updates BUILD.gn files from the BUILD.bazel files in their directories. Without
## -d, syncs every directory whose BUILD.gn contains the bazel2gn sentinel.

set -eo pipefail

_script_dir="${BASH_SOURCE[0]%/*}";
if [[ "${_script_dir}" == "${BASH_SOURCE[0]}" ]]; then _script_dir="."; fi
readonly _script_dir

# shellcheck source=/dev/null
source "${_script_dir}/../lib/vars.sh" || exit $?
fx-config-read

# shellcheck source=/dev/null
source "${_script_dir}/../lib/bazel_utils.sh" || exit $?

declare -r BAZEL2GN_TARGET="//build/tools/bazel2gn"

BAZEL2GN_BIN="$(fx-get-bazel-workspace)/bazel-bin/build/tools/bazel2gn/bazel2gn_/bazel2gn"
readonly BAZEL2GN_BIN

dir_list_file=""

function main {
  local build=true
  local directories=()
  while [[ "${#}" -ge 1 ]]; do
    case "${1}" in
      -d|--directory)
        shift
        directories+=("${1}")
        ;;
      -h|--help)
        fx-command-help
        exit 0
        ;;
      --no-build)
        build=false
        ;;
      *)
        fx-error "Unexpected command line arg ${1}"
        fx-command-help
        exit 1
    esac
    shift
  done

  # Without explicit directories, bazel2gn discovers all directories whose
  # BUILD.gn contains the bazel2gn sentinel.
  local -a dir_list_args=()
  if [[ "${#directories[@]}" -gt 0 ]]; then
    # Write the directories to a temporary file.
    dir_list_file="$(mktemp /tmp/bazel2gn-dirlist-XXXXXX)"
    trap 'rm -f "${dir_list_file}"' EXIT
    for directory in "${directories[@]}"; do
        printf "%s\n" "${directory}" >> "${dir_list_file}"
    done
    dir_list_args=(--directory_list "${dir_list_file}")
  fi

  if [[ "${build}" == "true" ]]; then
    fx-run-bazel false "$(fx-get-bazel)" build --config=host "${BAZEL2GN_TARGET}"
  fi

  "${BAZEL2GN_BIN}" \
    "${dir_list_args[@]}" \
    --fuchsia_dir "${FUCHSIA_DIR}" \
    --gn_bin "${PREBUILT_GN}" \
    --buildifier_bin "${PREBUILT_BUILDIFIER}"
}

main "$@"